July, 2013 PROGRESS IN PHYSICS Volume 3 LETTERS TO PROGRESS IN PHYSICS The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere I. Continuous Emission and Condensed Matter Within the Chromosphere Pierre-Marie Robitaille Department of Radiology, The Ohio State University, 395 W. 12th Ave, Columbus, Ohio 43210, USA. [email protected] The continuous spectrum of the solar photosphere stands as the paramount observation with regard to the condensed nature of the solar body. Studies relative to Kirchhoff’s law of thermal emission (e.g. Robitaille P.-M. Kirchhoff’s law of thermal emission: 150 years. Progr. Phys., 2009, v. 4, 3–13.) and a detailed analysis of the stellar opacity problem (Robitaille P.M. Stellar opacity: The Achilles’ heel of the gaseous Sun. Progr. Phys., 2011, v. 3, 93–99) have revealed that gaseous models remain unable to properly account for the generation of this spectrum. Therefore, it can be stated with certainty that the photosphere is comprised of condensed matter. Beyond the solar surface, the chromospheric layer of the Sun also generates a weak continuous spectrum in the visible region. This emission exposes the presence of material in the condensed state. As a result, above the level of the photosphere, matter exists in both gaseous and condensed forms, much like within the atmosphere of the Earth. The continuous visible spectrum associated with the chromosphere provides the twenty-sixth line of evidence that the Sun is condensed matter. In order to explain the occurrence of the dark lines properly account for the thermal spectrum. The generation of in the solar spectrum, we must assume that the solar a continuous solar spectrum has become an insurmountable atmosphere incloses a luminous nucleus, producing hurdle for these models [7]. Though gaseous opacity calcu- a continuous spectrum, the brightness of which ex- ceeds a certain limit. The most probable supposi- lations have been used in an attempt to account for the Sun’s tion which can be made respecting the Sun’s consti- emission, such calculations are of no value in mirroring the tution is, that it consists of a solid or liquid nucleus, simple graphitic spectrum on Earth, which the solar spectrum heated to a temperature of the brightest whiteness, strongly emulates. Therefore, gaseous opacity calculations surrounded by an atmosphere of somewhat lower cannot have any lasting merit in generating the continuous temperature. spectrum of the Sun [7]. The emission of a thermal spectrum ff Gustav Robert Kirchho , 1862 [1] requires an underlying thermal mechanism, not a large sum When Gustav Kirchhoff was contemplating the origin of of non-thermal processes [7]. Condensed matter is required, the solar spectrum [1], he was probably unaware that struc- as illustrated by earthly black bodies (see [3,4] and references tures beyond the photosphere also had the ability to emit con- therein). In fact, the continuous spectrum of the Sun acts as tinuous spectra. Still, he understood that continuous thermal the most important line of evidence that the Sun is condensed emission was a property of the condensed state [1]. Gases matter (see [8–14] and references therein). This was recog- emit in bands [2] and even compressed gases cannot produce nized long ago by Gustav Kirchhoff: gases cannot properly the required thermal spectrum, outside the confines of an en- account for the solar spectrum [1]. closure and in the absence of a perfect absorber [3,4]. The presence of continuous thermal emission by the pho- Despite these physical realities, over the course of the tosphere is complemented in the outer atmosphere of the Sun. past 150 years, scientists have moved away from Kirchhoff’s The chromosphere also supports weak continuous emission. realization that the solar surface must be comprised of con- Hence, an additional line of evidence that the Sun is com- densed matter. Instead, gaseous solar models were adopted prised of condensed matter can be harvested by extending (e.g. [5,6]). Sadly, Kirchhoff himself enabled this misstep Kirchhoff’s insight to the solar atmosphere, above the pho- through his erroneousformulation of the law of thermal emis- tospheric surface. sion (see [3,4] and references therein). Discounting problems The weak continuous spectrum of the chromosphere [15– with the law of emission [3,4], it can be said that the gaseous 18] has drawn the attention of solar observers for over 100 models have been based on a false premise: that the thermal years [19–22]. The great astronomer, Donald Howard Men- spectrum of the Sun could be generated using a vast combi- zel [23], commented as follows on its nature: “. we as- nation of non-thermal processes [7]. The solar opacity prob- sumed that the distribution in the continuous chromospheric lem [7] reflects the fact that the gaseous models can never spectrum is the same as that of a black body at 5700o, and Pierre-Marie Robitaille. Continuous Emission and Condensed Matter Within the Chromosphere L5 Volume 3 PROGRESS IN PHYSICS July, 2013 that the continuous spectrum from the extreme edge is that mains weak, it demonstrates the presence of condensed mat- of a black body at 4700o. There is evidence in favor of a ter within a gaseous matrix, much like drops of water can lower temperature at the extreme limb in the observations exist within the gaseous atmosphere of the Earth. In this re- by Abbot, Fowle, and Aldrich of the darkening towards the gard, the intensity of the chromospheric emission spectrum limb of the Sun” [22]. From early days, the continuous chro- can provide some sense of material densities in this layer. mospheric spectrum was known to vary in temperature with The presence of a continuous visible thermal spectrum in the height [24–27]. Consequently, solar observers rapidly in- chromosphere thereby constitutes the twenty-sixth line of ev- troduced temperature variations with increasing height into idence (and the sixth Planckian proof [34]) that the Sun is their atmospheric models (e.g. [17, p.187-213]; [18, p.271– comprised of condensed matter (see [8–14] and references 352]; [24–31]). therein for the others). At the same time, problemsremained surroundingthe for- mation of the weak continuouschromosphericspectrum. This Dedication layer of the Sun, in the context of the modern gaseous mod- This work is dedicated to Marge Marrone, for her friendship − els, had an average density of only ∼10 12 g/cm3 [32, p.32]. and example in leading a joyous life. In fact, as one proceedsout from the photosphereto the top of the chromosphere, the density was hypothesized to be chang- Submitted on: March 17, 2013 / Accepted on: March 20, 2013 ing from ∼10−7 g/cm3 to ∼10−15 g/cm3, respectively [33]. It First published online on: May 13, 2013 was known that in the chromosphere “. the intensity of the References emitted radiation is several tens of thousand times less than that of the photosphere” [32, p.32]. As a result, since the 1. Kirchhoff G. The physical constitution of the Sun. In: Researches on the Solar Spectrum and the Spectra of the Chemical Elements. Trans- gas models were reducing photospheric densities to the levels lated by H.E. Roscoe, Macmillan and Co., Cambridge, 1862, p. 23. of laboratory vacuums, the chromospheric densities had to be 2. Robitaille P.M. The little heat engine: Heat transfer in solids, liquids, even lower. and gases. Progr. Phys., 2007, v. 4, 25–33. In order to explain the continuous chromospheric spec- 3. Robitaille P.M. Blackbody radiation and the carbon particle. Progr. trum, theoretical approaches (e.g. [16, 25–27]) exactly par- Phys., 2008, v. 3, 36–55. alleled the methods applied for treating the emission from 4. Robitaille P.M. Kirchhoff’s law of thermal emission: 150 years. Progr. the photosphere (see [7] for a complete discussion). In early Phys., 2009, v. 4, 3–13. contributions, attention focused on neutral H, H−, Rayleigh 5. Bahcall J.N. and Pinsonneault M.H. Standard solar models, with and without helium diffusion, and the solar neutrino problem. Rev. Mod. scattering, and electron scattering (see [17, p.151–157] and Phys., 1992, v. 64, no.4, 885–926. [26,27]). This was precisely because, devoid of condensed 6. Bachall J.N., Pinsonneault M.H. and Wasserburg G.J. Solar models matter, no other mechanism could be invoked. A continu- with helium and heavy-element diffusion. Rev. Mod. Phys., 1995, v. 67, ous spectrum, from which Menzel had extracted black body no. 4, 781–808. temperatures [22], was being explained using processes un- 7. Robitaille P.M. Stellar opacity: The Achilles heel of the gaseous Sun. related to any experimental production of a thermal spectrum Progr. Phys., 2011, v. 3, 93–99. on Earth [7]. Such approaches remain in use, but have al- 8. Robitaille P.M. A high temperature liquid plasma model of the Sun. ready been dismissed relative to explaining the occurrence of Progr. Phys., 2007, v. 1, 70–81 (also in arXiv: astro-ph/0410075). continuous spectra [7]. 9. Robitaille P.M. Liquid metallic hydrogen: A building block for the liq- uid Sun. Progr. Phys., 2011, v. 3, 60–74. Conversely, the position is now adopted that the presence 10. Robitaille P.M. Liquid metallic hydrogen II: A critical assessment of of a continuous spectrum in the visible range within the chro- current and primordial helium levels in Sun. Progr. Phys., 2013, v. 2, mosphere [15–18] represents a direct manifestation of con- 35–47. densed matter in this region of the solar atmosphere. The 11. Robitaille J.C. and Robitaille P.M. Liquid metallic hydrogen III. In- proper means of explaining continuous emission in the visi- tercalation and lattice exclusion versus gravitational settling and their ble region of the electromagnetic spectrum, especially when consequences relative to internal structure, surface activity, and solar winds in the Sun.